2181723233 has 4 divisors (see below), whose sum is σ = 2181866388. Its totient is φ = 2181580080.

The previous prime is 2181723199. The next prime is 2181723251. The reversal of 2181723233 is 3323271812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 852172864 + 1329550369 = 29192^2 + 36463^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2181723233 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2181723233.

It is not an unprimeable number, because it can be changed into a prime (2181723253) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45566 + ... + 80247.

It is an arithmetic number, because the mean of its divisors is an integer number (545466597).

Almost surely, 2^2181723233 is an apocalyptic number.

It is an amenable number.

2181723233 is a deficient number, since it is larger than the sum of its proper divisors (143155).

2181723233 is a wasteful number, since it uses less digits than its factorization.

2181723233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143154.

The product of its digits is 12096, while the sum is 32.

The square root of 2181723233 is about 46708.9202722563. The cubic root of 2181723233 is about 1296.9798198709.

The spelling of 2181723233 in words is "two billion, one hundred eighty-one million, seven hundred twenty-three thousand, two hundred thirty-three".